Taxonomy and Classification

Who developed Linnaean classification?

Carl Linnaeus

What is each group known as in Linnaean classification?

A taxon (singular)/ taxa (plural)

How are the taxa arranged in Linnaean classification?

They are arranged in a hiercarchy

What are the two features of a hierarchy?

• Each smaller group is within a larger group

• There is no overlap between two groups at the same level

Name the taxa, in order from largest to smallest, in Linnaean classification.

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

What are taxa represented as in an euler diagram?

Circles within circles

When are two organisms said to be members of the same species?

When they are capable of breeding to produce fertile offspring

How are binomial names of species written?

• Genus with an uppercase letter followed by species with a lowercase letter

• Italics in print, underlined if handwritten

What is an advantage of binomial naming?

Scientists around the world can use the same names, regardless of their language

What is the main difference between Linnaean classification and phylogenetic classification?

Linnaean classification looks at physical characteristics whereas phylogenetic classification looks at evolutionary relationships

Which type of diagram is used to represent phylogenetic classification?

A phylogenetic tree

What are the three key features of a phylogenetic tree?

• Time progresses from the base of the tree to the tips of the tree

• Each node represents the most recent common ancestor for onward branches

• Species that are most closely related share the most recent common ancestor

What is a node on a phylogenetic tree?

The place where branches connect

What are the two modern methods used to find out how closely related two species are?

• Genome sequencing

• Immunology

What are the three things that genome sequencing can show?

• The base sequence of DNA

• The base sequence of RNA

• The amino acid sequence in proteins

In genome sequencing, what is the relationship between DNA sequences and how closely related two species are?

The more similar the DNA base sequence between two species, the more closely related the two species are

Why do more distantly related species have more differences in their DNA?

Because there has been more time for mutations to accumulate

What is the first stage in using immunology to test how closely related species A and species B are?

Extract albumin protein from species A

Where is albumin protein found?

In the blood plasma

What is the second stage in using immunology to test how closely related species A and species B are, after albumin has been extracted from species A?

Albumin from species A is injected into species C (e.g. a rabbit or mouse), and species C produces antibodies in response

What is the third stage in using immunology to test how closely related species A and species B are, after species C has produced antibodies?

Albumin from species B is added to a test tube containing antibodies complementary to albumin from species A. The greater the amount of precipitate formed, the more closely related species A and species B

What is produced when albumin binds to antibodies?

A precipitate

What is courtship behaviour?

Behaviour carried out to increase the likelihood of successful mating so that offspring have the maximum chance of survival

What are five ways in which courtship behaviour can increase the likelihood of successful mating?

• Attracts members of the same species

• Attracts members of the opposite sex

• Indicates a readiness to mate

• Stimulates mating and the release of gametes

• Encourages a bond for parents to successfully raise young together (a pair bond)